Kurzfassung

Hintergrund

Scaling CMOS technology has provided high density, high speed, and low power consumption electronic circuits. However, due to the constant shrinking of device dimensions the leakage currents – especially at standby – have become a serious issue. A possible solution to circumvent the standby power problem is to introduce non-volatile information storage in logic circuits. By this circuits can be shut down completely without loss of information and energy is only consumed when logic states are changed. For achieving this goal one needs to introduce non-volatility in the basic building blocks like Flip Flops (FF). Non-Volatile FFs (NVFF) store inter-mediate computing data in non-volatile mode and offer these immediately when the circuit is re-powered.

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Lösung

To overcome the above described problem the logic functionality of the flip flop is shifted from the CMOS into the magnetic domain. This is realized by spin transfer torque RAM like stack structures sharing a magnetic free layer, which realizes the flip flop logic by constructive or destructive superposition of two synchronously acting spin-transfer torques (Fig. 1). The operation result is saved via the magnetization orientation in the shared free layer.

Clever stacking and arrangement of several of these devices and their intrinsic logic allow the creation of an extremely dense shift register. By arranging the flip flops in two or more levels and two phase shifted clocking signals, the flip flops couple in a way that the information held by one shared free layer is successively passed via spin-transfer torque effect to the corresponding next shared free layer (Fig. 2).

Anwendungsbereiche

Flip flops and shift registers are essential parts of modern electronics. Together with its excellent achievable integration density our invention fits perfectly into large scale and very large scale integration of state-of-the-art CMOS technology. Due to the non-volatility, fast switching, high endurance, and radiation hardness of our flip flops - especially - field programmable gate arrays and their demanding applications in digital signal processing, medical imaging, computer vision, speech recognition, cryptography, bioinformatics, radio astronomy, metal detection and many more will benefit from our invention.